Nikon Speedlight & HVX200E
 

Looking for advice to sync a Nikon strobe for recording 720p at 10 frames per
second

The SB-25 is capable of Guide Number 12 metres for 2 seconds at 10 Hz at ISO 320 (20 frames total)

So F2 at 6 metres is within range, or, if bounced F2 at 3 metres


Of course the strobe will need to be sync'd to the shutter.

John,

You've probably already figured this out, but you can't do what you're proposing - and not sure why you'd even want to try. Suffice it to say that no video camera made sends out a triggering sync-signal that a still-camera strobe could communicate with.